EU leaders are curious to meet the British prime minister when he joins the Eastern Partnership Summit in Riga.They know him of old, of course, but for many this is a potentially new David Cameron, freshly elected with an unexpected majority.Many leaders got rather irritated with the prime minister in the long lead up to the election. They felt he played too much to the Eurosceptic gallery at home when abroad on EU business.Will this new David Cameron be a man they can work with, they wonder? They’d like to.